Wound exudate removal and isolation system

ABSTRACT

A wound exudate removal and isolation system includes a porous dressing, a canister in fluid communication with the dressing, and a first valve positioned between the dressing and the canister. The first valve is positionable between an open position and a closed position. A disposal line is fluidly connected to the canister and includes a second valve that is positionable between an open position and a closed position. A pump is fluidly connected to the canister and is configured to draw wound exudate from the dressing into the canister when the first valve is open and the second valve is closed. The pump is configured to force wound exudate from the canister into the disposal line when the first valve is closed and the second valve is open.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/591,324, entitled “Wound Exudate Removal and Isolation System,” filedAug. 22, 2012, which is a continuation of U.S. patent application Ser.No. 11/634,719, entitled “Wound Exudate Removal and Isolation System,”filed Dec. 6, 2006, and issued as U.S. Pat. No. 8,273,074 on Sep. 25,2012, which application claims the benefit of U.S. ProvisionalApplication No. 60/742,755, entitled “Wound Exudate Removal andIsolation System,” filed Dec. 6, 2005, and these applications areincorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to wound management. More particularly,the present invention pertains to a wound management system that employsreduced pressure to remove wound exudate and a dressing that willcontain and isolate the wound where the dressing must remain on thewound for a prolonged period of time.

2. Description of Related Art

The recent protracted combat operations of the U.S. Armed Forces in bothAfghanistan and Iraq have been remarkable in the comparatively low levelof fatalities compared to other conflict involving U.S. Armed Forces,such as the combat operations in Viet Nam. The reason for thecomparatively low level of fatalities is because of the dramaticimprovements that have been made in protective body armor and medicalcare. Significant improvements have been made to procedures andtechniques for stabilizing and removing injured personnel from thebattlefield to a facility where medical care may be administered bypersonnel with proper equipment. While there has been a dramaticdecrease in the loss of life, there also has been a correspondingincrease in the number of service members wounded. As in many combatsituations, a frequent injury to those in ground combat operations is adeep, traumatic wound. Many military trauma wounds are inherentlycontaminated and can become severely infected because of prolongedcontact with the ground on the battlefield or lengthy periods withouttreatment. Field medics are taught how to irrigate and/or clean deepwounds and then cover the wound with some type of wound dressing. Thewound dressing performs several functions. A dressing often includes apowder, an ointment, or a salve, which may kill some of the toxicbacteria that have entered the wound. Second, the dressing covers thewound to help prevent entry of additional toxic bacteria. Third, thedressing decreases the chance of cross contaminating other wounds on apatient's body. Fourth, the dressing absorbs fluids or exudate from thewound.

When wounds are large or deep, however, several treatment problemsarise. Because medical evacuation routes can extend thousands of miles,it is not uncommon for wounded soldiers to experience several days inthe medical evacuation process. While wounded personnel are intransport, it is generally not possible to provide the type of woundtreatment care available in a hospital. A gauze dressing may not havesufficient fluid retention capacity to adequately absorb all of theexudate from some wounds, and so may become saturated with exudate.Saturated dressings may not be easily exchanged for non-saturateddressings during medical evacuation and transport by aircraft orground/water transport vehicles. A typical mounting arrangement inmedical transport/evacuation vehicles involves stacking patient gurneysthree or four high, often against a wall or bulkhead. Such stacking ofgurneys may limit access to exudating wounds of those patients on thegurneys such that medical personnel often cannot readily tend todressings or any other equipment used to protect wounds.

During all parts of the medical evacuation process, there is a need toprovide wound exudate management and wound isolation with the woundcontained in a closed protective environment. Further, there is a needto remove and isolate wound exudate so that the wound exudate, abiohazardous material, can be collected and properly discarded. Suchremoval and isolation of wound exudate will reduce cross-contamination,reduce the risk of infection, and facilitate effective wound managementduring the transport of injured soldiers. There is a need to provide asystem that is compact so that it may be easily carried and is notdependent on any external source of energy for operation. Finally, thereis a need to provide a system that will be U.S. Military FlightCertified, a non-capital level asset, and disposable.

BRIEF SUMMARY OF THE INVENTION

The problems presented by existing wound isolation systems and methodsare solved by the systems and methods of the present invention. A woundexudate removal and isolation system in accordance with one embodimentof the present invention includes a porous dressing, a canister in fluidcommunication with the porous dressing, and a first valve positionedbetween the porous dressing and the canister. The first valve ispositionable in an open position to allow fluid flow and a closedposition to prevent fluid flow between the porous dressing and thecanister. A disposal line is fluidly connected to the canister, and asecond valve is operably positioned within the disposal line. The secondvalve is positionable in an open position to allow fluid flow and aclosed position to prevent fluid flow through the disposal line. A pumpis positioned in fluid communication with the canister and is operableto draw wound exudate from the porous dressing into the canister whenthe first valve is open and the second valve is closed. The pump furtheris operable to force wound exudate from the canister into the disposalline when the first valve is closed and the second valve is open.

In accordance with another embodiment of the present invention, a woundtreatment apparatus includes a means for dressing a wound, a means fordrawing exudate from the wound into a canister, a means for isolatingthe wound, and a means for forcing exudate from the canister.

In accordance with another embodiment of the present invention, a woundstasis and isolation apparatus includes an open-cell, reticulated foamdressing having an average pore size less than about 200 microns. Adrape is provided to cover the foam dressing and the wound. A pump ispositioned in fluid communication with the foam dressing to draw woundexudate from the wound at a pressure less than about 125 mmHg tomaintain wound drainage and moisture control at the wound but minimizetissue in-growth into the foam dressing.

In accordance with another embodiment of the present invention, a methodof providing stasis and isolation to a wound is provided. The methodincludes positioning an open-cell, reticulated foam dressing adjacentthe wound, the foam dressing having an average pore size less than about200 microns. A drape is positioned over the foam dressing and the wound,and a reduced pressure of less than about 100 mmHg is applied to thefoam dressing.

Other objects, features, and advantages of the present invention willbecome apparent with reference to the drawings and detailed descriptionthat follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simple illustration of one embodiment of the disclosedcompact, self-powered, wound exudate removal and isolation system;

FIG. 2 is a schematic diagram of the wound exudate removal and isolationsystem according to FIG. 1; and

FIG. 3 is a schematic diagram of an alternative embodiment of the woundexudate removal and isolation system in which a valve is activated byrotating the canister.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the invention. To avoid detail not necessary to enable those skilledin the art to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined only by the appended claims.

FIG. 1 is a simple illustration of one embodiment of the disclosedcompact, self-powered, wound exudate removal and isolation system 100 ofthe present invention. As shown in FIG. 1, system 100 provides for thecollection and disposal of wound exudate through a dressing, which canremain on a wound and be effective well beyond typical dressing changeintervals and throughout the entire medical evacuation process.Accordingly, the disclosed system 100 protects the person with a wound,those caring for the person with the wound, and others in closeproximity.

The wound exudate removal and isolation system 100 provides a dressingand a cover 110 over the wound, which draws exudate from the wound andmoves the exudate to an exudate collection system 120 through theapplication of a vacuum, or reduced pressure. With traditional reducedpressure delivery systems, the distribution of reduced pressure at thewound site is used to encourage new tissue growth. The wound exudateremoval and isolation system 100 is preferably used to isolate, protect,and provide stasis to the wound site until the patient arrives at amedical facility where the wound may be properly treated. The system 100is therefore configured to provide adequate wound drainage and moisturecontrol capabilities, while minimizing the in-growth of new tissue intothe dressing.

FIG. 2 is a schematic diagram of the wound exudate removal and isolationsystem 100 according to an embodiment of the present invention. As FIG.2 illustrates, a porous dressing 1.0 is used to create a protectiveenvironment over the wound. Dressing 1.0 is preferably formed from anopen-cell, reticulated foam. Alternatively, the dressing may be formedby other materials that are suitable for manifolding pressure across thewound. For example, a solid sheet of material (e.g. a sheet of silicone)having projections on one side may allow the distribution of pressure atthe wound through the flow channels formed between the projections.Instead of or in addition to the projections, small holes may beprovided in the sheet of material to allow the manifolding of pressure.Whatever type of dressing is used, the dressing 1.0 should have theability to distribute a reduced pressure to properly draw wound exudateaway from the wound. While the system 100 is not designed to encouragegranulation tissue growth, studies have found that wounds exposed toreduced pressure may granulate substantially in as little as 48 hours.To assist in the eventual removal and replacement of dressings, thewound contact surface of dressing 1.0 is designed to minimize tissuegrowth thereby facilitating wound contact well beyond typical 48-72 hourdressing-change intervals.

When a foam dressing is used, the dressing 1.0 dressing includes poresof a size that allow wound exudate to pass from a wound into tubing1.2., but minimize the in-growth of tissue into the pores. The averagepore size is typically between about 40 and 200 μm, and preferably about100 μm. The pore sizes associated with dressing 1.0 are typicallysmaller than the pore sizes associated with dressings used to promotewound healing. The porous dressing 1.0 may also have anti-microbialproperties. In one embodiment, the dressing may be coated or impregnatedwith an antimicrobial agent such as silver.

A drape 1.1 is placed over the foam dressing 1.0 to isolate the woundand allow for the application of a reduced pressure to the wound 1.0through tubing 1.2. In one embodiment, tubing 1.2 is a plastic tubing.The dressing 1.0, the drape 1.1, and a tubing 1.2 may be contained in asmall, lightweight kit, which can be easily deployed with and stocked byForward Military Medical Units.

The reduced pressure applied to the dressing 1.0 is strong enough tocontinuously draw exudate from the wound through the tubing 1.2. Unlikereduced pressure systems that are used to promote the growth ofgranulation tissue at the wound, the primary purpose of system 100 is toisolate and contain wounds and remove exudate. While the reducedpressure applied to the wound through the dressing 1.0 may be adjusteddepending on the size of the wound and the porosity of the dressing 1.0,it is preferred that the pressure applied to the wound be less thanabout 125 mmHg. This particular pressure is typically considered theminimum pressure at which new tissue growth is accelerated in wounds;hence, it is desired to remain below this pressure to minimize newtissue growth. More preferably, the pressure applied to the woundthrough the dressing will be between about 25 and 75 mmHg.

Again referring to FIG. 2 for illustration, a check valve 2 prevents thebackflow of exudate into the wound. A push-to-open in-line valve 3 is influid communication with check valve 2, positioned downstream from thewound. Downstream from the push-to-open in-line valve 3 is anon-removable, drainable canister 8 in fluid communication with valve 3.In one embodiment, canister 8 is drainable and constructed from a rigidmaterial. A disposal line 14 is fluidly connected to a drainage outlet15 of the canister 8. A valve 4 is positioned on the disposal line 14 influid communication with the canister 8. Both valves 3, 4 areselectively positionable in either an open position or a closed positionto allow or prevent fluid flow through the valve 3, 4. Preferably, theplacing of valve 3 in an open position results in the valve 4 beingplaced in a closed position. Similarly, the placing of valve 3 in aclosed position results in the valve 4 being placed in an open position.A cam wheel 5 may be operably connected to both valves 3, 4 tomechanically coordinate the simultaneous positioning of the valves 3, 4.

Since the system 100 may be placed at the wound for extended periods oftime during patient transport, it may be desired to drain the canister 8while leaving the remainder of the system 100 in place. Valves 3, 4 areprovided to allow drainage of the canister 8 when full or when desiredby the person attending to the wound. During the application of reducedpressure to the wound, valve 3 is open to provide fluid communicationbetween the dressing 1.0 and the canister 8. In this configuration,valve 4 is closed to prevent drainage of the canister 8. To drain thecanister 8, valve 3 is closed and valve 4 is opened. The closing ofvalve 3 prevents reduced pressure from being applied to the wound, whilethe opening of valve 4 allows wound exudate in the canister 8 to drainthrough the disposal line 14. Optionally, a disposable container 7 maybe connected to the disposal line 14 to collect the wound exudatedrained from the canister 8. The disposable container 7 may be aflexible, vented disposal bag. When the disposable container 7 is full,it may be removed and replaced with an empty container.

Reduced pressure is provided to the dressing 1.0 through the canister bya pump 11 that is fluidly connected to the canister. In one embodimentpump 11 is a battery-operated vacuum/pressure pump. Alternatively, thepump 11 may be manually operated, or may be any other pump suitable forinducing the pressures disclosed herein. As the pump 11 applies areduced pressure to the dressing 1.0 through the canister 8, woundexudate is drawn from the wound and deposited in canister 8. Thisoperation occurs when the valve 3 is in an open position and the valve 4is in a closed position.

As previously described, the canister 8 may be drained by positioningvalve 3 in a closed position and valve 4 in an open position. While thedrainage operation may be facilitated by gravitational force, the woundexudate may alternatively be forced out of the canister 8 into thedisposal line 14 by the pump 11. To facilitate forced drainage of thecanister 8, a three-way valve 9 is fluidly connected between thecanister 8 and an inlet of the pump 11. The valve 9 is selectivelypositionable between an active position and a vent position. In theactive position, the valve 9 allows fluid communication between thecanister and the inlet of the pump 11. In the vent position, the inletof the pump 11 is vented. Another three-way valve 10 is fluidlyconnected between the canister 8 and an outlet of the pump 11. The valve10 is selectively positionable between an active position and a ventposition. In the active position, the valve 10 allows fluidcommunication between the canister and the outlet of the pump 11. In thevent position, the outlet of the pump 11 is vented. The positioning ofthe valves 9, 10 is linked such that a positioning of the valve 9 in theactive position results in a positioning of the valve 10 in the ventposition. Similarly, a positioning of the valve 9 in the vent positionresults in a positioning of the valve 10 in the active position.

When valve 9 is positioned in the active position and valve 10 ispositioned in the vent position, the pump 11 is configured to draw woundexudate from the dressing 1.0 into the canister 8. In this reducedpressure configuration, valve 3 is positioned in the open position andvalve 4 is positioned in the closed position. When valve 9 is positionedin the vent position and valve 10 is positioned in the active position,the pump 11 is configured to provide a positive pressure to the canisterto force wound exudate from the canister 8 into the disposal line 14. Inthis positive pressure configuration, valve 3 is positioned in theclosed position and valve 4 is positioned in the open position.

A hydrophobic filter 8.1 also may be included in fluid communicationwith the canister 8 to prevent fluid from entering the tubing attachedto pump 11 and valves 9 and 10.

In one embodiment, a sensor may be operably associated with the canister8 to detect when the canister 8 is full of wound exudate. The sensor maybe operably connected to the valves 3, 4, 9, 10 to automatically adjustthe operation of the system 100 from a reduced pressure system to apositive pressure system so that exudate is moved from the canister 8 tothe disposable container 7 when the canister 8 is full.

The system may further include a safety alarm system that provideseither an audio signal or a visual signal if the system is not operatingproperly. The safety alarm system is configured to avoid producing falsealarms in response to typical patient conditions that may occur duringthe medical evacuation process. However, some events that may bedetected by the safety alarm system include, but are not limited to,leak detection events, blockage events, full canister events, lowpressure events, high pressure events, and low battery events.

The system may also include blood detection sensors to preventexsanguination or the removal of copious or unhealthy amounts of bloodfrom a patient.

As shown in FIG. 3, the valve directing the flow of exudate may bemanually activated by rotation of the canister 8.

It should be apparent from the foregoing that an invention havingsignificant advantages has been provided. While the invention is shownin only a few of its forms, it is not just limited but is susceptible tovarious changes and modifications without departing from the spiritthereof.

1-19. (canceled)
 20. A wound stasis and isolation apparatus comprising:an open-cell, reticulated foam dressing having an average pore size lessthan about 200 microns, the foam dressing being positionable adjacent awound; a drape to cover the foam dressing and the wound; and a pump influid communication with the foam dressing to draw wound exudate fromthe wound at a pressure less than about 125 mmHg to maintain wounddrainage and moisture control at the wound but minimize tissue in-growthinto the foam dressing.
 21. The apparatus of claim 20, wherein theaverage pore size of the foam dressing is less than or equal to about100 microns.
 22. The apparatus of claim 20, wherein the pore size of thefoam dressing minimizes tissue in-growth but allows drainage of fluidsfrom the wound.
 23. The apparatus of claim 20, wherein the pressure isbetween about 25 and 75 mmHg.
 24. The apparatus of claim 20, furthercomprising: a canister-positioned between the foam dressing and the pumpto collect the wound exudate, the canister having a drainage outlet; andwherein the pump is selectively operable to force wound exudate from thecanister through the drainage outlet.
 25. The apparatus of claim 24,further comprising a disposable container positionable in fluidcommunication with the drainage outlet to collect wound exudate from thecanister.
 26. A method of providing stasis and isolation to a woundcomprising: positioning an open-cell, reticulated foam dressing adjacentthe wound, the foam dressing having an average pore size less than about200 microns; positioning a drape over the foam dressing and the wound;and applying a reduced pressure of less than about 100 mmHg to the foamdressing.
 27. The apparatus of claim 26, wherein the average pore sizeof the foam dressing is less than or equal to about 100 microns.
 28. Theapparatus of claim 26, wherein the pore size of the foam dressingminimizes tissue in-growth but allows drainage of fluids from the wound.29. The apparatus of claim 26, wherein the reduced pressure is betweenabout 25 and 75 mmHg.
 30. A wound stasis and isolation apparatuscomprising: an open-cell, reticulated foam dressing having an averagepore size less than about 200 microns, the foam dressing beingpositionable adjacent a wound; a drape to cover the foam dressing andthe wound; and a pump in fluid communication with the foam dressing todraw wound exudate from the wound.
 31. The apparatus of claim 30,wherein the average pore size of the foam dressing is less than or equalto about 100 microns.
 32. The apparatus of claim 30, wherein the poresize of the foam dressing minimizes tissue in-growth but allows drainageof fluids from the wound.
 33. The apparatus of claim 30, wherein thepump is adapted to minimize tissue in-growth into the foam dressing. 34.The apparatus of claim 30, wherein the pump is adapted to draw woundexudate from the wound at a pressure less than about 125 mmHg.
 35. Theapparatus of claim 30, wherein the pump is adapted to draw wound exudatefrom the wound at a pressure between about 25 mmHg and about 75 mmHg.36. The apparatus of claim 30, further comprising: a canister positionedbetween the foam dressing and the pump to collect the wound exudate, thecanister having a drainage outlet; and wherein the pump is selectivelyoperable to force wound exudate from the canister through the drainageoutlet.
 37. The apparatus of claim 36, further comprising a disposablecontainer positionable in fluid communication with the drainage outletto collect wound exudate from the canister.
 38. The apparatus of claim30, wherein the porous dressing includes an antimicrobial agent.
 39. Theapparatus of claim 38, wherein the antimicrobial agent is silver. 40.The apparatus of claim 38, wherein the antimicrobial agent is coatedonto the porous dressing.
 41. The apparatus of claim 38, wherein theantimicrobial agent is impregnated in the porous dressing.